diff --git a/Project.toml b/Project.toml
index 192fbd6cbc..742ba567da 100644
--- a/Project.toml
+++ b/Project.toml
@@ -25,7 +25,7 @@ DensityInterface = "0.4"
 FillArrays = "0.9, 0.10, 0.11, 0.12"
 PDMats = "0.10, 0.11"
 QuadGK = "2"
-SpecialFunctions = "0.8, 0.9, 0.10, 1.0"
+SpecialFunctions = "0.8, 0.9, 0.10, 1.0, 2"
 StatsBase = "0.32, 0.33"
 StatsFuns = "0.8, 0.9"
 julia = "1"